On the recent changes in surface temperature trends over India

Marked differences from global trends in terms of diurnal asymmetry of temperature trends were reported earlier for India, indicating that the warming over India was solely contributed by maximum temperatures. We report substantial recent changes in the nature of trends, using updated data sets up to 2003, with special focus on the last three decades. While all-India mean annual temperature has shown significant warming trend of 0.05°C/10yr during the period 1901-2003, the recent period 1971-2003 has seen a relatively accelerated warming of 0.22°C/10yr, which is largely due to unprecedented warming during the last decade. Further, in a major shift, the recent period is marked by rising temperatures during the monsoon season, resulting in a weakened seasonal asymmetry of temperature trends reported earlier. The recent accelerated warming over India is manifest equally in daytime and nighttime temperatures

Characteristic features of winter precipitation and its variability over northwest India

Northwestern parts of India receive considerable amount of precipitation during the winter months of December-March. Although, it is only about 15 of the annual precipitation, the precipitation is very important for rabi crops and to maintain the glaciers extend in the Himalaya, which melt and supply water to the rivers during other seasons. The precipitation is mainly associated with the sequence of synoptic systems known as 'western disturbances'. The precipitation has considerable spatial and temporal variability, with maximum precipitation occurring particularly over northern hilly regions, with decreasing influence southwards. The spatially coherent winter precipitation series has been prepared for the largest possible area comprising nine meteorological subdivisions of northwest India, which constitute about 32 of the total area of the country, having similar precipitation characteristics. The precipitation series has been statistically analysed to understand its characteristics and variability. The seasonal precipitation series is found to be homogeneous, Gaussian (normal) distributed and free from persistence. The precipitation variability has increased during the most recent three decades with more excess and deficient years

Long term temperature trends at major, medium, small cities and hill stations in India during the period 1901-2013

Industrialization and urbanization are the most dominant causal factors for long-term changes in surface air temperatures. To examine this fact, the long term changes in the surface-air temperatures have been evaluated by the linear trend for the different periods, i.e. 1901-2013, 1901-1970 and recent period 1971-2013 as rapid industrialization was observed during the recent four decades. In the present study, seasonal and annual mean, maximum and minimum temperature data of 36 stations for the period 1901-2013 have been used. These stations are classified into 4 groups, namely major, medium, small cities and hill stations. During the period 1901-1970, less than 50% stations from each group showed a significant increasing trend in annual mean temperature, whereas in the recent period 1971-2013, more than 80% stations from all the groups except small city group showed a significant increasing trend. The minimum temperature increased faster than that of the maximum temperature over major and medium cities, while maximum temperature increased faster than the minimum temperature over the small cities and hill stations. The annual mean temperature of all the coastal stations showed a significant increasing trend and positive correlation with Precipitable Water Vapour (PWV). The effect of PWV is more pronounced on minimum temperature than that of the maximum

Characteristic features of winter precipitation and its variability over northwest India

Northwestern parts of India receive considerable amount of precipitation during the winter months of December–March. Although, it is only about 15% of the annual precipitation, the precipitation is very important for rabi crops and to maintain the glaciers extend in the Himalaya, which melt and supply water to the rivers during other seasons. The precipitation is mainly associated with the sequence of synoptic systems known as ‘western disturbances’. The precipitation has considerable spatial and temporal variability, with maximum precipitation occurring particularly over northern hilly regions, with decreasing influence southwards. The spatially coherent winter precipitation series has been prepared for the largest possible area comprising nine meteorological subdivisions of northwest India, which constitute about 32% of the total area of the country, having similar precipitation characteristics. The precipitation series has been statistically analysed to understand its characteristics and variability. The seasonal precipitation series is found to be homogeneous, Gaussian (normal) distributed and free from persistence. The precipitation variability has increased during the most recent three decades with more excess and deficient years

Characteristic Features of Precipitation Extremes over India in the Warming Scenarios

The detection of possible changes in extreme climate events, in terms of the frequency, intensity as well as duration assumes profound importance on the local, regional, and national scales, due to the associated critical socioeconomic consequences. Therefore, an attempt is made in this paper to evaluate various aspects of future projections of precipitation extremes over India, as projected by a state-of-art regional climate modeling system, known as PRECIS (Providing REgional Climates for Impacts Studies) towards the end of the 21st century (that is, 2071–2100) using standardized indices. Study reveals that PRECIS simulations under scenarios of increasing greenhouse gas concentration and sulphate aerosols indicate marked increase in precipitation towards the end of the 21st century and is expected to increase throughout the year. However the changes in daily precipitation and the precipitation extremes during summer monsoon (June through September) season are prominent than during the rest of year. PRECIS simulations under both A2 and B2 scenarios indicate increase in frequency of heavy precipitation events and also enhancement in their intensity towards the end of the 21st century. Both A2 and B2 scenarios show similar patterns of projected changes in the precipitation extremes towards the end of the 21st century. However, the magnitudes of changes in B2 scenario are on the lower side

Portulaca oleracea inhibit vincristine induced peripheral neuropathy: involvement of ATP-sensitive K+ channels

Background: The Portulaca oleracea belonging to portulacaceae family. It is a herbaceous plant widely distributed throughout the world and used in traditional medicine for many ailments. The present study was to evaluate the antinociceptive action of petroleum ether extract of P. oleracea in vincristine induced peripheral neuropathic pain and the possible mechanisms involved.Methods: Peripheral neuropathy was induced in rats by administration of vincristine sulfate (50 μg/kg i.p.) for 10 consecutive days. The cold tail hyperalgesia was assessed by cold water tail immersion test. To identify the possible mechanisms involved in the antinociceptive action of petroleum ether extract of P. oleracea, acetic acid writhing method was employed. Mice were pretreated with naloxone, glibenclamide before petroleum ether extract treatment to identify the involvement of opioid and potassium channels, respectively.Results: The administration of petroleum ether extract of P. oleracea (100 and 200 mg/kg p.o.) for 10 days significantly attenuated vincristine-induced cold hyperalgesia. Pre-treatment with glibenclamide reversed the antinociceptive effect of P. oleracea, but the naloxone pre-treatment did not reverse the antinociceptive activity of P. oleracea.Conclusion: The results of the present study reveal the antinociceptive effect of P. oleracea in vincristine induced peripheral neuropathy and involving ATP-sensitive potassium channels pathway

On forecasting the Indian summer monsoon: The intriguing season of 2002

This year, the rainfall over India during the first half of the summer monsoon season was 30 below normal. This has naturally led to a lot of concern and speculation about the causes. We have shown that the deficit in rainfall is a part of the natural variability. Analysis of the past data suggests that there is a 78 chance that seasonal mean rainfall this year will be 10 or more below the long-term average value. We discuss briefly how forecasts for seasonal rainfall are generated, whether this event could have been foreseen, and share our perspective on the problems and prospects of forecasting the summer monsoon rainfall over the Indian region

Comparison of neonatal outcome parameters between thick and thin meconium stained liquor: a prospective study

Background: Meconium stained liquor is a commonly observed phenomenon in the day-to-day obstetric practice, the incidence being 12-22%. Meconium stained liquor can be considered as a normal physiological event in a term fetus in the absence of fetal heart rate abnormalities. It has greater significance as one of the parameters of fetal distress, when associated with abnormal fetal heart rate pattern. The aim of the present study was to study the association of, fetal heart rate abnormalities, mode of delivery and neonatal outcome with different grades of meconium stained liquor.Methods: A prospective study was conducted in one hundred and fifty cases of meconium stained liquor beyond 37 weeks gestation admitted to the labor room in a tertiary care Centre. Depending on the consistency of meconium, the patients were divided into two groups namely, Thick meconium stained liquor (group K) and Thin meconium stained liquor (group N). Maternal conditions, Intrapartum fetal heart rate pattern, Apgar scores and neonatal morbidities were studied in relation to the grade of meconium. The proportions between the two groups were compared using chi-square test and Fisher’s exact t-test.Results: The incidence of post term pregnancy (p=0.004), unbooked (p=0.007) status and oligohydramnios (p=0.01) were significantly higher among group K when compared to group N. Non-reassuring fetal heart rate pattern (p=0.002) and Apgar score ≤7 (p=0.02) were significantly higher in group K. In group K, non-reassuring fetal heart rate pattern and reduced beat to beat variability were significantly associated with low Apgar score (p=0.01).Conclusions: Neonatal outcomes like low Apgar score, meconium aspiration syndrome are strongly associated with thick meconium stained liquor. Visual grading of liquor into thick and thin meconium stained may help in timely obstetric intervention leading to a better neonatal outcome

Sea level changes along the Indian coast: Observations and projections

Sea level changes can be of two types: (i) changes in the mean sea level and (ii) changes in the extreme sea level. The former is a global phenomenon while the latter is a regional phenomenon. Estimates of mean sea level rise made from past tide gauge data at selected stations along the coast of India indicate a rise of slightly less than 1 mm/year; however these estimates need to be corrected by including the rates of vertical land movements, whose measurements are not available at present. Simulation results of a regional climate model, HadRM2, were analysed for the northern Indian Ocean to provide the future scenarios of the occurrence of tropical cyclones in the Bay of Bengal for the period 2041-60. This model simulations consist of a control run with concentration of CO2 kept constant at 1990 levels and a perturbed run with transient increase in the concentrations of CO2 (GHG) according to the IS92a scenario for the period 2041-2060. The simulation results show increase in frequencies of tropical cyclones in the Bay, particularly intense events during the postmonsoon period, for the increased GHG run. A storm surge model was used to compute the surges associated with the cyclones generated by the climate model. The storm surge model was forced by the wind field from HadRM2 over the model domain and tides prescribed along the open boundary from a global tidal model. The frequency of high surges is found to be higher in the model run forced by winds from increased GHG run than in the model run forced by winds from the control run